This invention relates generally to conduit joints for misaligned or flexing conduits, and more particularly to a spherical decoupling joint for misaligned conduits.
Joining conduits is common in many products and systems, including vehicle exhaust systems that extend between an engine exhaust and an exhaust aftertreatment system such as a selective catalytic reaction system, (“SCR”). Ideally, the engine exhaust and the inlet to an exhaust aftertreatment system would be perfectly aligned and at a constant spacing during assembly and use. Nonetheless, in practice, the engine exhaust and aftertreatment device inlet are seldom aligned, and during use rarely at a constant spacing. Further, bellows permit only a very limited amount of rotational movement. The degree of rotational or twist provided by a bellows connection is as little as one degree.
To accommodate offsets, variable and changing spacing, and vibrations, it has been accepted in the industry to us a bellows-type conduit with folds that flex to accommodate misalignment and differential spacing. Bellows systems overcome these problems, but are expensive to manufacture, install, maintain, and replace.
It has been proposed to use a spherical telescoping joint to accommodate misaligned conduits and variable spacing. The spherical portion of the joint included a pair of spaced apart spherical joints each having a male portion fit into a female portion, and both have mating spherical surfaces that can pivot relative to one another to accommodate misalignment. Between the spherical joints is another telescoping joint to accommodate variable spacing between the components and vibrations. Such a joint is practical in theory, but known manufacturing methods render the joints impractical because of poor fit, leaks, high friction between joint parts and high manufacturing costs. These problems are exacerbated when such a joint is used in high-temperature and rugged environments, such as vehicle exhaust systems.
Thus, there is a need for a reliable and well-sealed conduit joint that accommodates misalignment, variable spacing, vibrations, and high temperatures that is relatively inexpensive to manufacture.